Improvement in iron truss-bridges



UNITED STATES PATENT OFFICE.

J. II. LINVILLE, OF ALTOONA, PENNSYLVANIA, ASSIGNOR TO HIMSELF AND J. L. PIPER, OF SAME PLAOE.

IMPROVEMENT IN IRON TRUSS-BRIDGES.

Specification forming part of Letters Patent No. 34,183, dated January 14, 1862.

To a/ZZ whom it may concern.'

Be it known that I, J H. LINVILLE, of Altoona, in the county of Blair and State of Pennsylvania, have invented a new and useful Improvement in Iron Truss-Bridges; and I do hereby declare that the following is a full, clear, and exact description of the same, reference being had to the accompanying drawings, forming part of this specilication, in which- Figure 1 is a side elevation of two panels of a truss-bridge constructed according to my invention. Fig. 2 is a transverse vertical section of the same. Fig. 3 is a plan of the top chords and lateral braces. Fig. lisa plan of the bottom chords and lateral braces. Fig. 5 is a horizontal section of one of the posts.

Similar letters of reference indicate corresponding parts in the several figures.

My invention consists, first, in' a novel construction of thelower chords and Inode of applying the same, in combination with the posts and other parts of the truss; second,in a novel construction of the posts ot wrought and cast iron.

To enable others skilled in the art to make and use my invention, I will proceed to describe its construction and operation.

O A L O A L are the posts; B B, the sections of the top chords; C O, the sections of the bottom chords; D D, the diagonal tensionbraces or suspension-rods; E E, counter-diagonal tension-braces; F F, lateral struts between the top chords; G G, lateral diagonal tension-braces between said chords; I I, transverse struts between the lower chords and lower ends of the posts; II H, lateral diagonal tension-braces between the lower chords and lower ends of the posts; B B', door-beams; O O', longitudinal timbers supporting tracks.

The bottom chords C C are each composed of a series of wide thin eye-bars, of wroughtiron, of a length corresponding with the distances between the posts on one side of the truss, placed on edge to enable them to give vertical support to the roadway and fitted outside of the bases L L of the posts and between ribs S S, formed on the said bases, as shown in Figs. 2 and 4. tended. in width at their ends and drilled to receive connecting-pins P P-one at the base The bars O are ex` of each post-the said pins passing through the'said ribs S S and being supported by the suspension-bars D D, which, as well as the counterdiagonals E E, are also fitted between other and similar ribs S S, the lower ends of the said bars being made with eyes for the reception of the said pins. The said chords, the ribs S S, and the diagonal rods D D and E are so disposed or distributed as to obviate all danger of bending the connecting-pins P P, which can only yield by being sheared otf by the tensile strain on the chords and diagonals, and the chords being thus well supported at short intervals support the floorbeams and track without the employment of auxiliary beams for this purpose.

The principal portions A A of the posts O A L O A L each consist of two rolled plates of wrought-iron a a (see Figs. 2 and 5) of semi-octagonal or other semi-polygonal form in their transverse section, secured Vtogether at intervals by rivets .I J or by bands shrunk around them, binding them firmly to the filling or distance pieces b, which are placed between them at suitable distances apart. The said plates cara are close together at top and bottom, but sprung apart at the middle ot' their length to render them capable of resisting a greater compressive force and to allow the diagonal counter-braces E E to pass through the posts without cutting' away any of the material. The posts are completed by casting around the wrought-iron portion A the bases L and capitals 0,015 any desired shape. The wrought-iron portion A may also be constructed of two semicircular T or L shaped sections, sprung apart, connected together, and terminating in cast bases and capitals in a manner similar to the two semipolygonal pieces a a. The advantage of this construction of the posts, besides that of allowing the counter-braces to pass through them without their being weakened by cutting away the metal, is that they are' more iiexible than cast-iron posts and less liable to injury by shocks.

The upper chordsB Bare made of cast-iron in sections of a length equal to the distances between the centers of the posts, said sections having' the central portions made of octagonal or other polygonal or circular form in their transverse section and terminating in rectangular form with mid-ribs R R (see Fig. 2) at their ends, which abut together over the posts to resist the vertical crushing strain re sulting from the action of the diagonals, and afford a greater abutting surface to resist and distribute the horizontal compression of the top chord. These mid-ribs and the outside plate of the chord pass through guides e con the top plates of the posts, and are thus maintained in line and position. The unusual width given to the abutting ends of the sections ot the top chords increases the lateral stiiness of the chords and allows the tensionrods D D in double canceled trusses to pass outside of the posts and at sufcient distance apart to admit of screws and nuts on the ends of the said rods for the purpose of adjustment. The several sections of the top chords may be formed of wroughtiron with castiron ends in the same manner as the posts O A. L O A L.

M M are angle-blocks placed over the joints of the sections of the top chord and between guide-pieces d d, provided thereon to form bearings for the nuts ff, which are fitted to the screws of the said rods.

The upper lateralstruts F F, of cast-iron, rest in pockets or bearings in the sides of the top chords. The lateral rods G G pass through the chords and are tightened by nuts K K, turning against angle-bosses Z Z on the outsides ot the chords. vWhen the bridge consists ot' three trusses, the bosses Z Z are used on both sides of the chords of the center truss, as shown at the right-hand side of Fig. 3, a jam-nut being used at one side of the truss and a sleeve-nut V on the other side for the twofold purpose of adjusting the lateral rod Y of the third truss in such manner that the two systems of lateral bracing may act independently of each other, which is an advan-v tage in the raising of the bridge and also in its subsequent use. Besides this advantage it (this system of bracing) obviates the necessity of passing all the rods through the chords.

The lower lateral tension-braces H H consist of short rods connected, as shown in Fig.

eral struts have each a concave opening in .the lower parts of their ends to drop over the Aconnecting-pin, and they should bear upon the plates N N. These plates transmit the strain from the rods H H to the struts I I ,without straining the ribs S S of the bases of the posts.

I do not claim the use of eye-bars or links as chains of suspension-bridges or as tensionbraces of truss-bridges; but

What I claim as my invention, and desire to secure by Letters Patent, is-

1. The construction of the lower chords of truss -bridges of series ot" wide and thin drilled eye-bars C C, applied on edge between ribs S S on the bottoms of the posts and connected by pins P P, supported in the diagonal tension-braces D D and E, all substantially as herein described.

2. The posts O A L O A L, composed each of two wrought-iron plates or bars a a, distance-pieces b b, and rivets J J or their equivalents, and cast-iron bases L L and capitals O O, the Whole combined as herein specified.

J. H. LINVILLE.

Witnesses:

W. H. WILSON, Jos. M. WILsoN. 

